The Mighty Fine 409 is one of General Motors’ legendary big-block engines, the successor to the original 348 cube “W” engine, and one that was found in the Impala Super Sport upon its debut back in 1960.

The single-four version of the engine produced 360 horsepower, and the dual-quad version like the one in this video was delivered from the factory with 409 horsepower – one horse per cube, which was pretty stout for the day. Subsequent versions of the 409 were able to crank out 425 horsepower later in the model run, but the engine was replaced in 1965 by the 396-cube Mark IV big-block engine that’s still found in many classics today.

The 409 just isn’t seen very often anymore, and parts are getting hard to come by, so it’s nice to see one running in decent shape.

409 engines (and all GM “W” series engines) had a unique combustion chamber setup, as the chamber was in the upper part of the cylinder rather than in the cylinder head itself, a design that made great torque and horsepower but was subsequently replaced by the more conventional chamber-in-head design Mark IV piece.

The engine in this video has been rebuilt using a 454 crankshaft and connecting rods, along with a set of Ross stroker pistons and an Isky Z33 camshaft.  C.H. Enterprises rebuilt the heads with a set of 7/16″ screw-in studs, new seals, stainless steel valves, and a set of COMP Cams Magnum roller rockers.

Dual quad Carter AFB carburetors have been professionally built by C.H. Enterprises, and the rest of the engine appears to have been dressed to be as period-correct as possible. The stroker engine is estimated to make 500 horsepower and 520 ft./lbs. of torque, an easy task for a breathed-on 409 to pull off.

The engine was for sale when the video was posted, but as that was a year ago today we’re not sure if it’s still available. Regardless, a 409 rumblin’ through your speakers on a Friday afternoon is a good way to head into yet another winter weekend. And if you’re feeling nostalgic, click the video below.